西村 庸夫

Nobuo NISHIMURA

愛媛大学医学部第三内科

The Third Department of Internal Medicine, Ehime University Medical School

キーワード : Sound velocity, Attenuation coefficient, Crossed beam method, Fatty liver, Liver-kidney contrast

We have recently developed an apparatus for measuring the sound velocity and attenuation coefficient in the liver by a crossed beam method for use in the non-invasive quantitative diagnosis of fatty liver. The results obtained with it were as follows.
The sound velocity was 1,575±19 m/sec in the 12 patients with normal livers and 1,531±26 m/sec in the 20 patients with fatty livers. In the patients with fatty liver, the sound velocity was significantly lower than in those with normal livers. Concerning the relationship between the fat content and the sound velocity, a significant negative correlation of r=-0.73 was noted. The highest attenuation coefficient was recorded in fatty livers. If a liver-kidney contrast was recognized by US, in cases with a normal sound velocity, fatty deposits were scarcely present. Thus the sound velocity measurement was highly specific for fatty liver.
Liver biopsy was conducted in 6 patients with chronic inactive hepatitis and in 20 patients with fatty liver. Liver tissue specimens 15 mm long were stained with Amido-Black 10B. The area ratio of the unstained portion (that is, the fat deposits) was determined using a texture analyzing system (manufactured by Leitz Co.). These results were compared with the hepatic sound velocity and attenuation coefficient. By simultaneous measurement of the hepatic sound velocity and attenuation coefficient, the sensitivity of diagnosis was increased. The accuracy of diagnosis of the degree of fatty change also proved to be very high.